Field of the Invention
The present invention relates generally to firearms, and more particularly toward a manually reciprocated gun stock for controlled rapid fire of a semi-automatic firearm.
Description of Related Art
Various techniques and devices have been developed to increase the firing rate of semi-automatic firearms. Slide Fire Solutions LP, of Moran, Tex., Applicant of this present invention, markets a proprietary slide-action stock under the trademark SLIDE FIRE. The SLIDE FIRE slide-action stock is described for example in detail in US 2012/0240442, published Sep. 27, 2012 and US 2012/0311907 published Dec. 13, 2012, the entire disclosures of which are hereby incorporated by reference and relied upon.
The slide-action stocks in these exemplary citations include a shoulder stock having a rearwardly facing butt end adapted to be pressed into the shoulder of a user, a pistol grip adapted to be grasped by the user's hand, and a finger rest configured to stabilize the end of a user's trigger finger stretched in front of the trigger of the firearm while the remaining fingers of the user's hand clench the pistol grip. The shoulder stock and pistol grip and finger rest are fixed together as a monolithic handle unit that, in use, is held tight to the user's body. When used in a rapid-fire slide-action mode of operation, the firing unit portion of the firearm—namely the barrel, receiver and trigger—are manually reciprocated back-and-forth in the handle unit in counterpoise with the recoil from each fired round of ammunition. The distance between the butt end of the shoulder stock and pistol grip is fixed in the prior art examples. That is, the trigger pull length, which is generally defined as the distance between butt end of the shoulder stock and the trigger in a center-fire rifle, is non-adjustable. As a result, users with exceptionally long or short arms, or that wear especially thick clothing, could find the firearm fit to be less than ideal. Shooting accuracy may suffer as a result of poor fit.
Adjustable and/or collapsible shoulder stocks are made for non-slide-action semi-automatic long rifles, including as two examples those produced by Magpul, Inc. and Tapco, Inc. Such prior art adjustable shoulder stocks usually include a lever-actuated latch that is manipulated by the user to selectively place a small plunger in any one of several adjustment holes aligned in a row along the bottom of a buffer tube (or of a comparable tube-like feature) that extends rearwardly from the firearm receiver. To adjust the shoulder stock length, i.e., the trigger pull length, a user manually withdraws the plunger (via the lever actuator of the latch) against a spring force then slides the shoulder stock to a preferred adjusted length position. Upon release of the lever actuator, the plunger seats in the nearest adjustment hole thus securing the shoulder stock in the length-adjusted position.
Such prior art adjustable shoulder stocks are generally incompatible with a slide-action reciprocating handle. For one reason, slide-action handles may use the same row of adjustment holes along the buffer tube (or tube-like feature) as a lock-out feature to selectively impede the slide-action mode of operation. Another reason that prior art adjustable shoulder stocks have been deemed incompatible with a slide-action reciprocating handles is that there has been no effective way to couple the prior art adjustable stock to the pistol grip and to a finger rest as a monolithic handle unit while incorporating a reciprocating interface with the firing unit portion of the firearm. While those not well-acquainted with the art may naively suppose design of an adjustable slide-action handle to be a relatively straightforward engineering exercise, such is in fact not at all readily apparent to the skilled artisan due, at least in part, to the requirements that shoulder stock and pistol grip be integrated into a monolithic handle unit that, in use, remains held tight to the user's body while the firing unit portion of the firearm rapidly reciprocates back-and-forth. A still further reason that prior art adjustable shoulder stocks have been deemed incompatible with slide-action reciprocating handles is that a prior art adjustable shoulder stock is intended to be locked relative to the firing unit in an adjusted position for use. A shoulder stock locked in position relative to the firing unit would impede slide-action shooting.
Therefore, there exists a continuing need for further improvements in devices that will allow a firearms user to practice slide-action shooting in the most effective manner possible, and in which users of varying arm lengths may experience the sport with proper fit.